Methods of and apparatus for automatically deboning meat and obtaining meat from poultry legs and thighs have been proposed by patent documents U.S. Pat. No. 5,277,649, U.S. Pat. No. 5,401,210, and U.S. Pat. No. 6,699,116. While these automated processes have performed in the past with some degree of success, the mechanical complications and the necessary financial investment have put these processes within reach of only the largest meat processing industries. More recently, improved automated devices and processes for removing meat from an animal extremity such as from the leg of a chicken has been proposed. In this process, a leg comprising a drumstick and thigh is hung from a shackle by its ankle joint and the shackle and leg are moved along a processing path sometimes referred to as a cut-up line. The tendons that extend from the ankle joint are cut just below the ankle joint and the leg proceeds to a meat removal station. At this station, the meat may be grasped by a meat stripper just below the ankle joint where the cut has been made and the stripper is moved away from the shackle and the ankle joint held therein. In this way, the stripper strips the meat from the leg bone or tibia. Meat may then be stripped from the thigh bone or femur, after which the stripped meat is collected for further processing.
In addition to tendons attaching muscle to the ankle joint, a chicken leg also includes a small bone known as the fibula (sometimes called the pin bone or needle bone) that extends along the outside surface of the tibia. For the left leg, the fibula extends along one side of the tibia while for the right leg the fibula extends along the opposite side of the tibia. It is very important that the fibula not end up in the meat that is stripped from the leg and thigh because, if eaten, this small bone can cause damage to the digestive track of a human. Further, much of the fibula is made of cartilage, which is not always detectable by bone detecting devices downstream of a leg deboning machine. Accordingly, when cutting the tendons of the poultry leg below the ankle joint before the meat is stripped, it is critically important that the fibula not be cut in the process. In this way, the fibula remains with the tibia as the meat is stripped away and does not find its way into the stripped meat products that result from the process. In prior leg deboning machines, cutting the tendons while virtually never cutting the fibula or its attaching cartilage has posed problems and has resulted in some cases in undetected pieces of the fibula ending up in the final boneless meat product.
Accordingly, a need exists for a method and apparatus for selectively cutting the tendons of a poultry leg prior to a meat stripping operation while virtually never cutting the fibula in the process of cutting the tendons. It is to the provision of a method and apparatus that addresses this need that the present invention is primarily directed.